1. Field of Invention
The present invention relates generally to the field of fluid filters. More specifically, the present invention is related to a fluid filter with a replaceable filter element assembly. The device of this invention has particular application in providing a self-aligning, quick-and-easy assembling fluid filter element assembly.
2. Discussion of Prior Art
Until recently, the design of standard spin-on oil filters had not undergone major changes since introduction in the early 1960s. Recently, however, concerns regarding the environmental impact of millions of disposable oil filters have led to the development of reusable filter housings which incorporate replaceable filter elements. Replaceable filter elements contain less residual oil and break down far easier than typical disposable spin-on filters. The current inventor's earlier patent (5,411,659) introduced an exemplary replaceable filter element design. These replaceable filter elements, which are assembled infrequently and usually by do-it-yourself mechanics, must be correctly assembled and aligned within a filter housing to ensure proper operation of the filter and to prevent serious damage to a vehicle's engine. However, the related prior art often includes multi-piece filter and valve assemblies which can be mis-assembled or, at the least, mis-aligned during assembly.
The patent to Baldwin (3,557,958) teaches a standard, disposable oil filter anti-drainback valve positioned near the filter's base plate and constructed of a rubber-like material. While ease of assembly is discussed by this reference, the discussion is limited simply to improved placement of a separate valve seat.
The patent to Thornton (3,567,022) provides for a combination valve assembly, for a standard, disposable oil filter, which includes a relief valve and anti-drainback valve in an integral assembly.
The patent to Stack (3,957,640) provides for a cone-shaped elastomeric anti-drainback valve, for a standard, disposable oil filter, which positions the filter assembly into a correct position for assembly.
The patent to Bumb (3,984,318) provides for a simple to assemble anti-drainback valve which combines the bypass valve and anti-drainback valve on the same support. The example oil filter is of disposable, not reusable, construction.
The patent to Anderly et al. (5,256,280) provides for an anti-drainback valve which rests a valve diaphragm against a slanting valve seat.
The patent to Jones et al. (5,711,872) provides for a reusable filter which incorporates the relief valve as a permanent part of the replaceable filter cartridge.
The patent to Roll et al. (5,817,232) provides for a replaceable filter assembly which has the by-pass valve and anti-drainback valve in a "rebuild" kit separate from the filter element.
The patent to Smith et al. (5,830,371) provides for an alternative arrangement of by-pass valve and anti-drainback valve for a reusable oil filter.
The patent to Matsubara et al. (5,876,600) provides for a two-piece filter housing for a reusable oil filter which uses rotating grooves and channels within each half of the filter housing to keep the housing bodies aligned during assembly.
Whatever the precise merits, features and advantages of the above cited references, none of them achieve or fulfill the purposes of the present invention. Accordingly, it is an object of the present invention to provide for a replaceable fluid filter element assembly which is pre-assembled as a single unit.
It is another object of the present invention to provide for a replaceable fluid filter element assembly which assembles quickly, easily and correctly in a filter housing.
It is an additional object of the present invention to provide for a replaceable fluid filter element assembly which engages self-aligning features of a filter housing.
It is an additional object of the present invention to provide for a self-aligning, replaceable fluid filter element assembly which creates a fluid-tight seal within a filter housing without the need for an endcap spring element.
It is an additional object of the present invention to provide for a self-aligning, replaceable fluid filter assembly for use as an oil filter in an internal combustion engine.
These and other objects are achieved by the detailed description that follows.